Make Resque instrumentation tests a better simulation of real Resque usage

Instead of setting up the test process as if it were a Resque master process, and
then forking (implicitly via Resque::Worker#work), we now explicitly spawn a Resque
worker process for these tests.
Skip Resque tests on JRuby for want to an easy way of spawning background processes
Oops, suite_conditions don't stack - exclude both 1.8.6 and JRuby from resque tests
RUBY-998 Extracting changelog reading to easier script
Stick version of jdbc-sqlite3 to 3.7.2 since 3.7.2.1 crashes
RUBY-857 Defer Resque startup until after (potential) daemonization
RUBY-857 Defer Resque startup until after (potential) daemonization

For real this time.
RUBY-857 Make background Resque tests conditional on Ruby 1.9+
Adding a CHANGELOG entry for RUBY-875 and RUBY-992